Body Fat Calculator

Calculate your body fat percentage using the US Navy circumference method.

Men: 495/(1.0324-0.19077xlog(waist-neck)+0.15456xlog(height))-450; Women: Similar formula with different constants
Male, 180 lbs, 32 inch waist, 15 inch neck, 70 inch height: Body fat = 18.2% (Average), Fat mass = 32.8 lbs, Lean mass = 147.2 lbs

What is a healthy body fat percentage?

Healthy ranges by gender: Men - Essential: 2-5%, Athletes: 6-13%, Fitness: 14-17%, Average: 18-24%, Obese: 25%+. Women - Essential: 10-13%, Athletes: 14-20%, Fitness: 21-24%, Average: 25-31%, Obese: 32%+. "Six-pack visible" range: Men 10-12%, Women 16-19%. Health risks below essential fat (hormonal issues, organ damage) and above obese (metabolic disease, cardiovascular issues). Most people healthiest in fitness to average range.

How accurate is the Navy body fat method?

Navy method (circumference-based) accuracy +-3-4% compared to gold standard (DEXA, hydrostatic weighing). Advantages: Free, no special equipment, repeatable at home. Disadvantages: Doesn't account for fat distribution variations, can be off for very lean or obese individuals. Tips for accuracy: Measure same time of day, same conditions, multiple times and average, measure carefully at correct locations, use flexible tape measure. Good for tracking trends over time, not absolute precision.

What is the difference between body fat percentage and BMI?

BMI = Weight/Height ratio, doesn't measure body composition. Body fat % = Actual fat mass vs lean mass. Example: Muscular athlete - BMI 28 (overweight) but body fat 12% (fit). Skinny-fat person - BMI 22 (normal) but body fat 28% (high). Body fat % is superior measure of health and fitness. BMI quick screening tool for populations, body fat % shows true composition. Focus on body fat % for fitness goals.

How quickly can I reduce body fat percentage?

Safe fat loss: 0.5-1% body fat per month (1-2 lbs fat/week). Faster loss risks muscle loss, metabolic slowdown. Example: 20% body fat, 180 lbs - Goal 15% = lose 5% body fat = ~9 lbs fat = 2-4 months. Strategies: Calorie deficit 500-750/day, high protein (preserve muscle), strength training (maintain lean mass), adequate sleep, patience. Track measurements monthly - weight alone misleading (water, muscle). Sustainable beats rapid every time.